Wednesday, 21 January 2009

HEP 2008 chart

Symmetry Breaking just posted the 2008 topcites according to SPIRES. That list is a bit depressing to look at, as it is dominated by papers from the last century. Recent ideas cannot stand ground against Maldacena, Randall-Sundrum, ADD. To check what's new in town, instead, I compiled another ranking of most cited papers FROM 2008. I counted the ratio of the number of citations to the number of months the paper has been out. (I was too lazy to count days, which would be more adequate. Also, I included only the papers that have already acquired 50+ citations). Here is what's revealed.

70 citations/month, Five-Year WMAP Observations: Cosmological Interpretation, by WMAP Collaboration, arXiv:0803.0547 The absolute leader, even though they were hardly the news last year: one needs very large telescopes to tell the 5-year results from the 3-year ones. Nevertheless, quite deservedly, they keep receiving the credit for turning cosmology into a precision science.(Actually, there should be two more WMAP clones in this list: arXiv:0803.0586 and arXiv:0803.0732 who have received 32 and 22 citations/month respectively, but these two got disqualified for obscuring the view.)

26 citations/month, N=6 superconformal Chern-Simons-matter theories, M2-branes and their gravity duals, by Aharony, Bergman, Jafferis, Maldacena, arXiv:0806.1218.So this is the most cited 2008 theory paper... It constructs novel gravity duals that employ the notion of M2 branes. I have no idea how important this is. Go ask Jacques, who has a post on the Bagger-Lambert construction of M2 branes, and another one that includes a brief comment on the Aharony et al. paper.

26 citations/month, Observation of an anomalous positron abundance in the cosmic radiation, by PAMELA collaboration, arXiv:0810.4995.PAMELA was definitely the star of the last summer: the paparazzi affair was more widely discussed than Britney Spears' new look. On top of that, PAMELA's observation of a cosmic-ray positron excess in the energy range 10-100 GeV was readily interpreted as an indirect signature of dark matter annihilation/decay. This spawned a whole lot of theoretical activity, including the paper below.

19 citations/month, A Theory of Dark Matter, by Arkani-Hamed, Finkbeiner, Slatyer, Weiner, arXiv:0810.0713.Once again Nima set the direction. The paper proposes a model that explains the PAMELA excess and a few other mysterious astrophysical results. The crucial feature is the hidden sector hosting dark photons (cool name) with GeV scale masses.

16 citations/month, Superconformal Chern-Simons Theories and AdS(4)/CFT(3) Correspondence, by Benna, Klebanov, Klose, Smedback, arXiv:0806.1519.It is a new development related to the Aharony et al (number 2 on this list) who in turn is a new development related to the Baggert-Lambert construction of M2 branes...

13 citations/month, Averages of b-hadron and c-hadron Properties at the End of 2007, By Heavy Flavor Averaging Group, arXiv:0808.1297 That must be very important, even if Heavy Flavor Averaging Group sounds a bit ominously.

12 citations/month, M2 to D2 revisited, by Ho, Imamura, Matsuo, arXiv:0805.1202.It's a pity there is no R-branes yet in string theory; R2-D2 would make an even better title.

12 citations/month, M2-branes on M-folds, by Distler, Mukhi, Papageorgakis, Van Raamsdonk, arXiv:0804.1256I'm afraid I have run out of jokes on M2 branes. Given that I have no intelligent comments in store, I'll just skip to the next one.

11 citations/month, Three-flavour neutrino oscillation update, by Schwetz, Tortola, Valle, arXiv:0808.2016.Nobody expects the Spanish Inquisition...people out there are still working on neutrinos... Congratulations to Thomas - the only CERN theorist (now ex-) who has made it to this ranking.

In summary, 2008 in particle theory was the Baggert-Lambert year :-|. Way down below (6 citations/month) is the paper of D.T. Son on AdS/cold atoms correspondence, which I personally consider the most interesting one in the last year.

I find this list disappointing. It seemed to me that all year, most theorists were waiting with baited breath for LHC data, and not doing much of anything that was interesting, and this list reflects that. Not to be a stinker, but here's my assessment of this list:

WMAP: Great!

M2-branes: (all 5) Who cares? This is math, not physics (yet). Someone please tie this to the universe I see...

"A Theory of Dark Matter": For every measurement, there's some probability P that it's not real, or not what you think it is. I think P > 50% or so. This paper has attempted to explain so many things at the same time that it's almost guaranteed to be not realized in nature. In this case, Pamela/ATIC is probably from pulsar, DAMA is from a bizarre systematic in efficency for detecting the Auger photon from 40K decay, and the CDF muons are punch-through of their HCAL (this is a known problem and is why they added the outer muon system in Run II). I'll eat my shorts if this paper turns out to be right. Besides, BaBar/Belle are the right places to look for such light higgs states (and they are, and they don't see any -- yet). This paper is a good exercise for what we will be doing once we have LHC data. But, I think theorists should be more selective about believing experiments. (and the corollary is that experimentalists should be more selective in believing theorists -- or better yet, don't believe us at all and do everything as model-independent as possible)

Two of these are experiments, which is great. Being tied to data keeps us physicists. The last two are sort of summary papers, so no surprise there. The PDG also gets a lot of citations. Again good because these are tying us to data. The more papers in this list are data, the more likely we are to discover something. 5 are math, leaving (by my assessment) only one real theory paper.

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Résonaances is a particle physics blog from Paris. It's about the latest news and gossips in particle physics and astrophysics. The main goal is to make you laugh; if it makes you think too, that's entirely on your own responsibility...